Adhesive tapes of various types are supported on a release coated or treated carrier web and wound into a roll. The roll is supported in a package that encloses the roll in order to protect it against damage or contamination during storage, shipping and use. When it is time to use the tape, the carrier web is withdrawn from the package and the adhesive tape is to be separated from the carrier web so that the user can remove the tape therefrom and apply it in the desired manner.
One form of package that has been employed for packaging rolls of adhesive tape on a carrier web is a "blister pack" that comprises a thermoformed plastic cover element having a surrounding flange that is heat sealed to a flat base member. The roll of adhesive tape is carried between the cover element and the base element. In a known form of such package, the cover element is formed with a housing section that encloses the roll of tape and an exit section that is a formed channel. The carrier web is lead through the channel and then bent around an edge of the base member so that the tape will separate from the carrier web. An improved version of this general type of package is illustrated in U.S. Pat. No. 3,743,086, Aldrich, Adhesive Tape Dispenser Package; the package of this patent has an exit section of the cover element which bears against the top of the adhesive tape and thereby provides more dependable separation of the adhesive tape from the carrier web.
The adhesive tape in the above packages is generally cut into a series of individual markers arranged end-to-end on the carrier web. One benefit of using a blister pack as a storage and dispensing package is that individual markers can be applied by the user without touching and thereby contaminating the adhesive on the tape. The most common application technique to do this is to advance the tape around a sharp edge of the package to a point where about three-quarters of an individual marker has separated from the carrier web. The marker is positioned over the desired area of attachment while still attached to the carrier web. The separated portion of the marker is then pressed into position by finger pressure and the package is withdrawn to separate the remaining portion of the marker from the carrier web. In order to be able to use this application technique, a relatively high level of restraining force must be applied to the roll of tape in the package. If sufficient restraining force is not maintained during the withdrawal step, tape can be advanced during the package withdrawal action to such an extent that the subsequent marker following the one being applied will move to a position in which proper dispensing is not possible. When the subsequent marker has reached this position, it has to be manually removed from the carrier web; this raises the possibility of contaminating the adhesive by touching it and also results in a time-consuming process that is not nearly as convenient as the preferred application technique. Further, markers are often rendered unusable when this happens. These disadvantages can appear with the known packages discussed above.
It is very difficult to obtain proper restraining force or back tension when the adhesive tape is supported on a carrier web of plastic film, more so than if a paper carrier web is used. The smooth low friction surface of plastic film carrier web material significantly lowers the amount of back tension that can be obtained by channel restraining packages or friction between the end of the roll and the base member of the package. However, plastic film is the preferred material for the carrier web in many instances.
The present invention was developed to obviate the foregoing problems, and also to provide a dispensing package that is particularly useful for adhesive tape carried on a plastic carrier web.